J. Appl. Cryst.の発刊に際して

Lanthanide ions possess fascinating optical properties and their discovery, first industrial uses and present high technological applications are largely governed by their interaction with light. Lighting devices (economical luminescent lamps, light emitting diodes), television and computer displays, optical fibres, optical amplifiers, lasers, as well as responsive luminescent stains for biomedical analysis, medical diagnosis, and cell imaging rely heavily on lanthanide ions. This critical review has been tailored for a broad audience of chemists, biochemists and materials scientists; the basics of lanthanide photophysics are highlighted together with the synthetic strategies used to insert these ions into mono- and polymetallic molecular edifices. Recent advances in NIR-emitting materials, including liquid crystals, and in the control of luminescent properties in polymetallic assemblies are also presented. (210 references.)

Taking advantage of luminescent lanthanide ions

Fluorogenic and chromogenic chemosensors and reagents for anions.

The miniaturization of components used in the construction of working devices is being pursued currently by the large-downward (top-down) fabrication. This approach, however, which obliges solid-state physicists and electronic engineers to manipulate progressively smaller and smaller pieces of matter, has its intrinsic limitations. An alternative approach is a small-upward (bottom-up) one, starting from the smallest compositions of matter that have distinct shapes and unique properties-namely molecules. In the context of this particular challenge, chemists have been extending the concept of a macroscopic machine to the molecular level. A molecular-level machine can be defined as an assembly of a distinct number of molecular components that are designed to perform machinelike movements (output) as a result of an appropriate external stimulation (input). In common with their macroscopic counterparts, a molecular machine is characterized by 1) the kind of energy input supplied to make it work, 2) the nature of the movements of its component parts, 3) the way in which its operation can be monitored and controlled, 4) the ability to make it repeat its operation in a cyclic fashion, 5) the timescale needed to complete a full cycle of movements, and 6) the purpose of its operation. Undoubtedly, the best energy inputs to make molecular machines work are photons or electrons. Indeed, with appropriately chosen photochemically and electrochemically driven reactions, it is possible to design and synthesize molecular machines that do work. Moreover, the dramatic increase in our fundamental understanding of self-assembly and self-organizational processes in chemical synthesis has aided and abetted the construction of artificial molecular machines through the development of new methods of noncovalent synthesis and the emergence of supramolecular assistance to covalent synthesis as a uniquely powerful synthetic tool. The aim of this review is to present a unified view of the field of molecular machines by focusing on past achievements, present limitations, and future perspectives. After analyzing a few important examples of natural molecular machines, the most significant developments in the field of artificial molecular machines are highlighted. The systems reviewed include 1) chemical rotors, 2) photochemically and electrochemically induced molecular (conformational) rearrangements, and 3) chemically, photochemically, and electrochemically controllable (co-conformational) motions in interlocked molecules (catenanes and rotaxanes), as well as in coordination and supramolecular complexes, including pseudorotaxanes. Artificial molecular machines based on biomolecules and interfacing artificial molecular machines with surfaces and solid supports are amongst some of the cutting-edge topics featured in this review. The extension of the concept of a machine to the molecular level is of interest not only for the sake of basic research, but also for the growth of nanoscience and the subsequent development of nanotechnology.

Artificial Molecular Machines.

Artificial Organic Host Molecules for Anions

Synthesis and Protonation Behavior of the Macrocyclic Ligand 1,4,7,13- Tetramethyl-1,4,7,10,13,16-hexaazacyclooctadecane and of Its Bicyclic Derivative 4,7,10,17,23-Pentamethyl-1,4,7,10,13,17,23-heptaazabicyclo( 11.7.5)pentacosane. A Potentiometric and 1H and 13C NMR Study.

Bis-squaramide receptors L1-L4 bearing a dansyl moiety were synthesised and their potential applications as fluorescent probes towards non steroidal anti-inflammatory drugs naproxen and ketoprofen was investigated. A detailed photophysical characterization in CH3CN/DMSO solution (9 : 1 v/v) was conducted and demonstrated that the two macrocyclic receptors L1 and L2 show good sensitivity towards ketoprofen with an ON-OFF fluorescent response, while the two open chain receptors L3 and L4 behave similarly with the three guests considered. DFT theoretical calculations carried out on L2 and L4 as model receptors allowed to propose a possible coordination mode towards the guests. Finally, 1H-NMR spectroscopy in DMSO-d6/0.5% water solution demonstrated that the four receptors interact with the considered guests via H-bonds.

Fluorescent sensing of non-steroidal anti-inflammatory drugs naproxen and ketoprofen by dansylated squaramide-based receptors.

The cover feature image depicts a tetranuclear Cu2+/Ca2+/Ca2+/Cu2+ maltol-based platform, which has been proposed as a tool for the detection and sequestering of anionic species via a colorimetric mechanism or an indirect fluorescent sensing. The platform could possibly monitor the presence of anions of environmental interest in surface, waste- and drinking waters, returning a precious and practical service to the human community. As anions included among the emerging pollutants, non-steroidal anti-inflammatory drugs are possible targets of this system. More information can be found in the Research Article by E. Macedi, V. Fusi, and co-workers. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/cplu.202300041

Cover Feature: A Tetranuclear Copper(II)/Calcium(II) Complex as Dual Chemosensor for Colorimetric and Fluorescent Detection of Non‐Steroidal Anti‐Inflammatory Drugs (ChemPlusChem 5/2023)

The synthesis and characterization of the new macrotricycle 10,22,28,32-tetraoxa-1,4,7,13,16,18-hexaazatricyclo[17.5.5.57,13]tetratriacontane L is reported. Its basicity in aqueous solution has been investigated by potentiometric and spectroscopic (1H, 13C NMR) techniques. The basicity constants have been determined (25 °C, I= 0.15 mol dm–3) in two ionic media. Macrotricycle L behaves as a hexaprotic base: log K1= 10.27(3), log K2= 9.52(3), log K3= 7.12(3), log K4= 4.62(3), log K5= 2.80(3), log K6= 2.27(3) in NaClO4 and log K1= 10.09(3), log K2= 9.27(3), log K3= 6.54(3), log K4= 4.88(3), log K5= 3.75(3), log K6= 3.07(3) in NaCl. The constants relative to the equilibrium Cl–+ HnLn+⇌ HnLCl(n–1)+ have been measured: n= 5, log K= 2.48(3); n= 6, log K= 3.59(3). The crystal structure of L has been determined by single-crystal X-ray analysis. The compound crystallizes in a triclinic unit cell (space group P, Z= 2) with lattice constants a= 8.984(5), b= 12.122(2), c= 14.667(3)A, α= 109.52(2), β= 105.47(3), γ= 95.24(3)°. Least-squares refinement converged at R= 0.088 (R′= 0.075) for 3198 unique reflections with I > 4σ(I). The structure shows that the molecule has a skewed cylindrical shape, the bases being formed by the two N2O2 macrocycles with the N(CH2CH2)2 chains constituting the walls. The cylindrane L binds two Li+ ions and the resulting complex has been studied by 7Li NMR spectroscopy. Copper(II) and cadmium(II) complexes with L have been investigated in aqueous solution and their stability constants determined by potentiometric techniques. For both metals the following species have been found: [ML]2+, [MLH]3+, [ML(OH)]+ and [ML(OH)2].

Vieri Fusi

Papers

Synthesis and Protonation Behavior of the Macrocyclic Ligand 1,4,7,13- Tetramethyl-1,4,7,10,13,16-hexaazacyclooctadecane and of Its Bicyclic Derivative 4,7,10,17,23-Pentamethyl-1,4,7,10,13,17,23-heptaazabicyclo( 11.7.5)pentacosane. A Potentiometric and 1H and 13C NMR Study.

Fluorescent sensing of non-steroidal anti-inflammatory drugs naproxen and ketoprofen by dansylated squaramide-based receptors.

Cover Feature: A Tetranuclear Copper(II)/Calcium(II) Complex as Dual Chemosensor for Colorimetric and Fluorescent Detection of Non‐Steroidal Anti‐Inflammatory Drugs (ChemPlusChem 5/2023)

Synthesis, Crystal Structure and Ligational Properties of a New Macrotricyclic Ligand.

Synthesis and Coordination Properties of Highly Preorganized Polyamine Macrocycles